Cracked heat exchangers

[Chuck]

hand held digital carbonmonxide ppm reader. drill small hole in flue pipe near furnace, insert sensor tip, turn on furnace. readings should level out around 50 ppm or less. when blower comes on and readings increase this means there is a crack in heatexchangere. or a blocked secondary heatexchanger. dont leave probe in to long readings will get to high for meeter and can cause damage. there is no need to look for a crack at this point. furnace or heatexchanger needs to be replaced.

The CO reading on a furnace that has a cracked heat exchanger can do one of three things when the blower comes on; 1. It can rise, 2. It can fall. 3. It can stay the same.

Not all cracks are leaking so you won't find them all with only a CO reading.

And as Beenthere stated, there are other things that can cause erratic CO readings besides cracked heat exchangers.

[OldSchoolMech]

hand held digital carbonmonxide ppm reader. drill small hole in flue pipe near furnace, insert sensor tip, turn on furnace. readings should level out around 50 ppm or less. when blower comes on and readings increase this means there is a crack in heatexchangere. or a blocked secondary heatexchanger. dont leave probe in to long readings will get to high for meeter and can cause damage. there is no need to look for a crack at this point. furnace or heatexchanger needs to be replaced.

I suggest you put down your fancy Co Reader and get an old fashion Mirror and use your eyes.
How many "Upsales" do you get with that fancy trick? Might aswell have a Probe you stick in and a big Bad symbol lights up and tell the HO "Your Gonna need a new ones.This ones Bad see?" Sell them a new Furnace.

I dont get the water trick? Pour it on the top and you will see it inside the burner tubes?

[Joehvac25]

I was on one the other day, 15 yr old goodman piece o crap, flames rolling out, condensate box cracked and leaking. I told her it was time, old lady with money who lives on the lake and she gets pissed at me, it was In a crawl and I took pictures and showed her even. The part that made her mad was she put an inducer on 2 yr ago in an emergency. Why is it that the people with money always complain.


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[Chuck]

I was on one the other day, 15 yr old goodman piece o crap, flames rolling out, condensate box cracked and leaking. I told her it was time, old lady with money who lives on the lake and she gets pissed at me, it was In a crawl and I took pictures and showed her even. The part that made her mad was she put an inducer on 2 yr ago in an emergency. Why is it that the people with money always complain.


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The next question they ask is, can't you just weld the crack shut???

[Joehvac25]

The next question they ask is, can't you just weld the crack shut???

I usually tell them unless I have a few hose clamps, high temp silicone and an energy drink I really can't help them out lol.


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[Chuck]

I usually tell them unless I have a few hose clamps, high temp silicone and an energy drink I really can't help them out lol.


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[raeben]

Hello, I am owner of outdoor, commercial style combination unit being used in a residence. I've lived here 32 years and we have had 3 HVAC units in this period. The most recent is 9 years old. In my experience, most HVAC repair have little experience or at least seem to. On the phone they don't believe I have a combination unit and will not believe me. More than one repair person has told me we don't see these very often. So I have limited trust at this point. Still looking for an HVAC contractor I really feel I can trust.

There is some rust on the interior panel covering the heat exchanger. No one has taken this rust-streaked panel off or actually looked at the heat exchanger. But they see the rust and tell me, "Well if there is a crack in the heat exchanger it would be more expensive to fix it than repair it." You should replace the unit. No one has taken off this inner panel and actually looked at the heat exchanger NOR has anyone taken a digital manometer to the pressure switch.

We have several CO detectors running in the house, and no CO is detected.

However, I would like to find someone who will actually either take the inner panel off or do the test you describe and check the HE. Maybe this is just exterior housing rust and the HE is fine. IDK. Do you know anyone freelance or otherwise in the Northern Virginia area that I can hire to check this unit out properly before recommending a replacement?

Thanks.

[rundawg]

We have several CO detectors running in the house, and no CO is detected.

However, I would like to find someone who will actually either take the inner panel off or do the test you describe and check the HE. Maybe this is just exterior housing rust and the HE is fine. IDK. Do you know anyone freelance or otherwise in the Northern Virginia area that I can hire to check this unit out properly before recommending a replacement?

Do not just look for a guy who freelances in combustion problems.

You need to find someone certified in Carbon Monoxide and Combustion Analysis. Your best chance of finding someone who has been trained in this subject, is to go to the National Comfort Institutes (NCI) website, and search for a NCI Certified Professional.

You can put in your zip code and a list of contractors will come up that are near you.

http://www.myhomecomfort.org/find-a-contractor/

You will find the best trained experts in the field for the issues you describe.

They can also review with you the weaknesses of store bought CO detectors, and provide you with the reasons a Low Level CO monitor is a better option for alerting you to CO within the home.

[raeben]

Thanks for your quick response. I've found some one through NCI and will see them later this week. Also getting a low-level CO detector! It's crazy that the store bought ones don't help unless the level is already twice what it takes before a fireman dons his mask.

[rundawg]

Thanks for your quick response. I've found some one through NCI and will see them later this week. Also getting a low-level CO detector! It's crazy that the store bought ones don't help unless the level is already twice what it takes before a fireman dons his mask.

Excellent! Glad you were able to find someone.

[catmanacman]

Sounds like a run of the mill gas pack , I usually pop the top and perform a visual inspection of the hx

[raeben]

Sounds like a run of the mill gas pack , I usually pop the top and perform a visual inspection of the hx

How long (approximately) should that take? Maybe 2 hours max?

The company -- nice guys and all but they want me to consider a new install without doing this? I don't trust that approach! We get crazy weather high wind and rain, that may or may not have reached the HX. I'm paying for *another* company to come out and do an inspection.

They better pull the top off. If there's damage to the HX they should be able to show me, right?

Unit before this was installed in '84 and lasted until '07. 22 years. The HX is under warranty from Lennox for 20 years. I think they just assume (because they don't work on package units) that the labor costs would preclude repair of the HX. And on most furnaces they might, but not on a package unit around here.

[rundawg]

How long (approximately) should that take? Maybe 2 hours max?

If there's damage to the HX they should be able to show me, right?

Not all package units can you just undo 15+ screws and the top pops right off.

Some units have the condenser coil on top so the refrigerant piping keeps you from just pulling the top free.

With that said, a competent tech should at least be able to take photos of any HX damage to show you once he gets enough panels free to do an examination.

If you are standing there, he should be able to show you directly.

Time involved to do this? Depends on the unit and the techs experience.